505052-84-6Relevant academic research and scientific papers
A metal-A nd base-free domino protocol for the synthesis of 1,3-benzoselenazines, 1,3-benzothiazines and related scaffolds
Putta, V. P. Rama Kishore,Gujjarappa, Raghuram,Tyagi, Ujjawal,Pujar, Prasad P.,Malakar, Chandi C.
supporting information, p. 2516 - 2528 (2019/03/07)
Efficient protocols have been described for the synthesis of 1,3-benzoselenazines, 1,3-benzothiazines, 2-aryl thiazin-4-ones and diaryl[b,f][1,5]diazocine-6,12(5H,11H)-diones. These transformations were successfully driven towards the product formation under mild acid catalyzed reaction conditions at room temperature using 2-amino aryl/hetero-aryl alkyl alcohols and amides as substrates. The merits of the present methods also rely on the easy access of rarely explored bioactive scaffolds like 1,3-benzoselenazine derivatives, for which well-documented methods are rarely known in the literature. A broad range of substrates with both electron-rich and electron-deficient groups were well-tolerated under the developed conditions to furnish the desired products in yields up to 98%. The scope of the devised method is not only restricted to the synthesis of 1,3-benzoselenazines, but it was also further extended towards the synthesis of 1,3-benzothiazines, 1,3-benzothiazinones and the corresponding eight membered N-heterocycles such as diaryl[b,f][1,5]diazocine-6,12(5H,11H)-diones.
Exceptional isolation of both imine and enamine desmotropes of 4,1-benzothiazepines
Csomós, Péter,Fodor, Lajos,Csámpai, Antal,Sohár, Pál
experimental part, p. 3207 - 3213 (2010/05/19)
The desmotropy of differently substituted (R*)-3-ethoxycarbonyl-2-aryl-3,5-dihydro-4,1-benzothiazepines and 3-ethoxycarbonyl-2-aryl-1,5-dihydro-4,1-benzothiazepines was investigated. The target 4,1-benzothiazepines were obtained via the ring transformation of (2R*,2aS*)-2-chloro-2a-aryl-2,2a-dihydro-2H,4H-azeto[1,2-a][ 3,1]benzothiazin-1-ones with sodium ethoxide in ethanol. The β-amino ester intermediate of the ring-enlargement reaction was isolated. Surprisingly, the desmotropes obtained could be separated by column chromatography and proved to be unexpectedly stable in solution. Further comparative studies revealed the existence of only the enamine forms of regioisomeric 2-ethoxycarbonyl-3-aryl-4,5-dihydro-7,8-dimethoxy-1,4-benzothiazepine derivatives; in this case, no desmotropy occurred. The structures were proved by means of NMR and IR spectroscopy.
Novel β-lactam condensed 3-thiaquinolines: an efficient synthesis and structural characterization
Csomós, Péter,Fodor, Lajos,Bernáth, Gábor,Sinkkonen, Jari,Salminen, Jari,Wiinam?ki, Kirsti,Pihlaja, Kalevi
, p. 1002 - 1011 (2008/09/17)
Quinoline analog 2-aryl-4H-3,1-benzothiazine derivatives 8-13, obtained by the condensation of o-aminobenzyl chloride 1 with?substituted thiobenzamides 2-7, were transformed to azeto[2,1-a][3,1]benzothiazin-1-one derivatives 18-23a,b,c and 24d,e by reaction with the corresponding substituted acetyl chlorides 14-17 in the presence of triethylamine. The structures of the new molecules were determined by NMR spectroscopy and electron ionization (EI) mass spectrometry. The typical EI+ mass spectrometric fragmentations of 8-13 and 18-23a,b,c and 24d,e are discussed in detail.
Sulfur-containing heterocycles derived by reaction of N-thioacylamino alcohols with Lawesson's reagent and saponification of N-thioacylamino esters
Nishio, Takehiko,Sekiguchi, Hiroshi
, p. 203 - 212 (2007/10/03)
The treatment of 2-N-thioacylamino alcohols (1) with Lawesson's reagent [LR: 2,4-bis(p-methoxyphenyl)-1,3,2,4-dithiaphosphetane 2,4-disulfide] afforded the sulfur-containing heterocycles, 1,3-thiazolines (2) in moderate to good yields, exclusively. The sa
